I rebuilt the host using the 6.0.0 6921384 ISO so it is now the same version as the upgraded hosts (which were upgraded from 5.5 to 6.0.0 6921384). All hosts had their main management IP as vmk0 which was on the distributed switch, and a secondary management IP vmk5 on the standard switch. I'm not sure how this was setup.
When I setup HOST05, it automatically created a primary management IP vmk0 on the standard switch and I would like to move this to the distributed switch to match the other hosts, but I cannot figger out a way to do this. I tried removing the host from vCenter and re-adding it but that does not change the setup.